Water Films and Hydroplaning on Highways: Hydrodynamic Aspects

The quantification of water depths resulting from rain events on highways is presented using concepts of flows along flat plates. The hydrodynamics of the water film was developed by taking the basis of the fluid-surfaces interaction, generating equations for the depth of the films that reproduce adequately measured data considering the equilibrium between impulsive and resistive forces. To consider geometrical changes, corrective parcels were added, obtained through dimensional analysis involving the depth of the texture of the pavement. The exponents and coefficients of the formulation were adjusted to better reproduce literature data and check the adequacy of the obtained solutions. The hydroplaning phenomenon was treated using the integral formulation of the principles of conservation of mass and momentum, inserting information of the tread grooves in the control volume equations, which evidences its effect on the general hydroplaning velocity. Both the formulations (film thickness and hydroplaning) are presented in nondimensional form to allow their use with any system of units. The good correlations obtained between measurements and predictions show that the hydrodynamics of both the water films and the hydroplaning phenomenon were adequately quantified through the application of the basic physical principles. The resulting equations can help design purposes and be used in further studies on this theme.